Bone mineral density: Methods of measurement and its influence on primary stability of miniscrews

Objective:To verify whether bone mineral density (BMD) of cortical bone, trabecular bone, and total bone influence the primary stability of orthodontic miniscrews and to verify whether there is a correlation between the measurement of BMD by cone-beam computed tomography (CBCT) and central dual-energy x-ray absorptiometry (DEXA).Materials and Methods:Twenty bovine bone sections were extracted from the pubic and iliac bones from regions with cortical thicknesses of approximately 1 mm. The BMD of the total bone block was evaluated using two methods: CBCT and DEXA. The BMD of cortical, trabecular, and total bone in the region of interest (ROI) were also evaluated by CBCT. After scanning the bone blocks, 20 self-drilling miniscrews (INP®) 1.4 mm in diameter and 6 mm long were inserted into them. The peak implant insertion torque (IT) was registered. After this, the pull-out test (PS) was performed and the maximum force registered. The Pearson correlation test was applied to verify the correlations between variables.Results:The BMD of the total bone block verified by CBCT and DEXA showed a positive and strong correlation (r  =  0.866, P  =  .000). The BMD of the ROI for cortical bone influenced the IT (r  =  0.518, P  =  .40) and the PS of miniscrews (r  =  0.713, P  =  .001, Table 2). However, the total bone BMD (verified by CBCT and DEXA) and trabecular bone BMD presented weak and not statistically significant correlations with primary stability.Conclusions:There was a positive correlation between total bone block BMD measured by DEXA and CBCT. The cortical BMD influenced the IT and PS.     

The interference of the cleaning procedure of root walls with two different solvents on the adhesion of fiberglass intraradicular posts

Aim: This study was undertaken to examine the effect of root canal (RT) sealers content and the cleaning procedure of RT walls on bond strength (BS) of a fiber reinforced composite (FRC) post cemented with resin-based or zinc phosphate cement. Materials and methods: Forty bovine roots were divided into 2 groups (n = 20) and obturated with gutta-percha points plus Sealer 26 sealer or gutta-percha points plus N-Rickert sealer. In each group, half (n = 10) of intracanal walls was cleaned with ethanol and the other half with sulfuric ether. In each of these subgroups, half of intracanal posts (n = 5) were cemented with Bistite resin-based cement and half with zinc phosphate cement. Specimens were submitted to pull-out test and tensile force until post dislodgement. The maximum forces required for post removal was expressed in MPa, means were submitted to statistical analysis (Analysis of Variance Test, a = 0.05). Results: Fiber reinforced composite cemented with zinc phosphate were significantly more retentive than those cemented with Bistite (p < 0.05). Regarding the influence of eugenol-based sealer on post retention, there was a statistically significant difference (p < 0.05) only between groups cemented with Bistite, in which canals filled with N-Rickert + gutta-percha showed lower BS than canals filled with Sealer 26 + gutta-percha. Conclusion: Despite endodontic cement used, higher pull-out bond strength were obtained when posts were cemented with zinc phosphate. Clinical significance: The importance of ethanol or sulphuric ether application to properly replace water from intraradicular dentine still requires further investigations, especially to clarify if this technique may reduce the effect of aging and improve the stability of the bond, when used to cement fiber posts into the root canal. Keywords: Laboratory research, Dentin, Eugenol, Resin cements, Root canal filling material, Pull-out test, Cleaning procedure. How to cite this article: Gomes MF, Botta SB, Matos AB, Garone- Netto N. The Interference of the Cleaning Procedure of Root Walls with Two Different Solvents on the Adhesion of Fiberglass Intraradicular Posts. J Contemp Dent Pract 2012;13(3):275-279. Source of support: Nil Conflict of interest: None declared.     

Male clients of brothel prostitutes as a bridge for HIV infection between high risk and low risk groups of women in Senegal

OBJECTIVE: To explore the extent to which male clients of prostitutes have a role as a bridge in the spread of HIV into the general population of Dakar, Senegal. METHODS: A sexual behaviour HIV prevalence survey was carried out among clients of female prostitutes working in brothels recruited outside the prostitutes' rooms after the encounter. All men entering the house and leaving the women's rooms were asked to answer the questions and to donate saliva for HIV-1 and HIV-2 testing. RESULTS: Findings suggest that a proportion of clients form a potential bridge for HIV transmission between prostitutes and partners from the general population. They have unprotected sexual contacts with both brothel prostitutes, and steady and casual partners, and expose both unmarried and married women to HIV infection. Findings also indicate that wives are more exposed to HIV than other categories of women in the population. CONCLUSIONS: Clients of brothels' prostitutes have a significant potential for spreading HIV beyond the initial high risk behaviour groups in Senegal. Efforts should be provided to target specific groups at higher risk for HIV infection, such as young men from the densely populated working class neighbourhoods of Dakar, and women outside the commercial sex networks for HIV education and prevention.     

Antibody response in patients with cutaneous leishmaniasis infected by Leishmania (Viannia) braziliensis or Leishmania (Viannia) guyanensis in Brazil

The antibody response against Leishmania (Leishmania) amazonensis crude antigen was measured through the indirect immunofluorescent assay (IFA) and the immunoenzymatic assay (ELISA) in 114 patients with cutaneous leishmaniasis (CL) in Brazil. Fifty-four patients were infected by Leishmania (Viannia) braziliensis, and 60 patients had L. (V.) guyanensis infection. Patients were comparable by age, sex, disease duration and the Montenegro skin test diameter. L. (V.) braziliensis-infected patients showed significant lower number of ulcerated lesions, greater ulcerated area and higher proportion of lymph node enlargement. Sensitivity of IFA was 79.6% (95% CI 66.1-88.9) and 71.7% (95% CI 58.4-82.2) for L. (V.) braziliensis and L. (V.) guyanensis-infected patients, respectively (P=0.324). Sensitivity of ELISA was 98.2% (95% CI 88.8-99.9) and 85.0% (95% CI 72.9-92.5) for L. (V.) braziliensis and L. (V.) guyanensis-infected patients, respectively (P=0.018). Significant differences were observed in the magnitude of the antibody response before treatment with higher levels detected in L. (V.) braziliensis-infected patients by both serologic techniques. Eighty-four patients had serologic evaluations before and 12 weeks after treatment with meglumine antimoniate, 20 mg/kg/day for 20 days. Significant lower optic density values were observed after treatment with both species independent of cure or failure. Our data showed that L. (V.) braziliensis induces a higher antibody response against L. (L.) amazonensis antigens than L. (V.) guyanensis and that down-modulation of the antibody response occurs shortly during disease evolution after treatment. Moreover the data support the use of ELISA as a better tool for detection of antibodies in CL.     

Asymptomatic human carriers of Leishmania chagasi

In Brazil, programs based on elimination of infected dogs have not curtailed the spread of visceral leishmaniasis (VL), suggesting that other reservoirs of infection exist. Persons with active VL can infect the sand fly vector, but in endemic areas, persons with asymptomatic infections, whose infectivity to sand flies is unknown, are far more numerous. In this study, a polymerase chain reaction-based assay detected kinetoplast DNA of Leishmania chagasi in the blood of eight of 108 asymptomatic persons living with patients with recently diagnosed VL. These eight persons had low or unmeasurable levels of IgG antibodies to Leishmania, demonstrating the insensitivity of serology for subclinical infection. All eight persons had positive leishmanin skin test results, as did 70% of persons living in households of persons with active VL. Even if a small proportion of such asymptomatic persons are infective to sand flies, they represent a formidable reservoir of infection in endemic areas.